Solutions to problems which were satisfactory as recently as a few years ago may no longer provide viable alternatives. One such example involves recycling of bark as an unwanted by-product of the timber industry. Heretofore, much of the bark that devolves from harvesting timber and processing logs into lumber would have been relegated to a landfill. However, as available capacity in landfills diminish, other solutions must be found. In addition, concern has been expressed with respect to leaching of certain bark constituents such as tannins into ground water. Thus, relegating bark to a landfill is a less viable solution to the point where landfills will not allow bark. In fact some landfills presently do not accept bark.
Bark also has commercial value in other areas, such as when used for mulch, landscaping and fuel for cogeneration. However, commercially acceptable bark must be free from the debris which normally attends the processing, stock piling and transport of bark in bulk. For example, timber is typically stored in piles on a gravel surface and sprinkled with water to prevent decomposition and cracking from dehydration. The reason for the gravel surface is to support front end loaders which transport material from one pile to another. Contamination of the bark with gravel and fines, etc. result in the bark being unacceptable for commercial use.
A corollary to this problem involves the gravel itself. Gravel contaminated with bark is not commercially desirable either. Accordingly, a pressing need exists for clean bark and gravel which heretofore has gone unresolved.
The following patents reflect the state of the art of which applicant is aware and is tendered in direct response to discharge applicant's acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these citations when considered singly nor when analyzed in any permissible combination teach or render obvious the nexus of the instant application as particularly set forth hereinafter and as especially claimed.
______________________________________ INVENTOR PATENT NO. ISSUE DATE ______________________________________ C. H. Young 2,025,841 December 31, 1935 K. F. Tromp 2,139,047 December 6, 1938 O. Schoeneck 2,990,064 June 27, 1961 N. S. Lean, et al. 3,367,495 February 6, 1968 Siri, et al. 4,055,488 October 25, 1977 Cullom 4,813,618 March 21, 1989 ______________________________________
The patent to Tromp is of interest since he teaches the use of an apparatus for separating materials having the greatest coincidental structural similarity with that of applicant's device. However, strictly speaking, this teaching in Tromp is to non-analogous, unrelated endeavors and therefore any similarities between the instant invention and Tromp are merely coincidental. Moreover, structural differences and methodologies are apparent from even a cursory comparison between the two. For example, Tromp does not contemplate directing bark over a dam-like partition in such a way that the bark will have undergone cleansing by virtue of the turbulence attending the travel of the bark over the dam partition.
No bark-gravel separator exists which will remove bark having a specific gravity equal to or greater than that of water.
The remaining citations show the state of the art further and diverge even more starkly from the instant invention.